Up to now, display devices that have been practically applied mainly include cathode ray tubes (CRTs), liquid crystal displays (LCDs), vacuum fluorescent devices (VFDs), plasma displays (PDPs), organic light emitting diodes (OLEDs), field emitting displays (FEDs), and electroluminescent displays (ELDs).
An OLED (organic light-emitting diode) display device includes an anode, an organic light emitting layer and a cathode. Compared with an LCD display device, an OLED display device has advantages such as small thickness, light weight, wide viewing angle, active light emission, continuously tunable emission color, low costs, fast response speed, small energy dissipation, low driving voltage, wide operating temperature range, simple production process, high luminous efficiency, and flexible display. OLEDs have gained great attention from the industrial community and scientific community due to their advantages and promising application prospects un-comparable to other kinds of displays.
When manufacturing an OLED display, since the cathode is typically of a low work function metal, the anode needs high work function material to match with it. At present, commonly used anode materials are conductive polymer materials. However, electrical conductivities of polymer materials are poor compared with metal and indium tin oxide (ITO) materials.